JP6164121B2 - Water treatment equipment - Google Patents

Description

  The present invention relates to a water treatment apparatus provided with a reverse osmosis membrane module.

  High-purity pure water that does not contain impurities is used in the manufacture of pharmaceuticals and cosmetics, the cleaning of electronic parts and precision equipment, and the like. This type of pure water is generally produced by treating feed water such as groundwater and tap water with a membrane separator and purifying the permeated water obtained. The membrane separation device is provided with at least one reverse osmosis membrane module, and can produce permeated water and concentrated water from the supplied water. In the following description, the reverse osmosis membrane module is also referred to as “RO membrane module”, and the reverse osmosis membrane is also referred to as “RO membrane”.

  In the RO membrane module, a phenomenon occurs in which silica contained in raw water is deposited as a scale on the surface of the RO membrane. When scale deposition occurs on the surface of the RO membrane, the water permeability is reduced. For this reason, in a reverse osmosis membrane separation apparatus equipped with an RO membrane module, it is important to operate so that scale deposition does not occur on the surface of the RO membrane.

  Conventionally, in order to suppress precipitation of silica-based scale, a silica concentration sensor (silica concentration detection means) has been provided, and the flow rate of the supply water supplied to the RO membrane module is within a range where the silica concentration of the concentrated water does not exceed the silica solubility. There is known a reverse osmosis membrane separation apparatus that operates by adjusting the recovery rate, which is the ratio of the flow rate of permeated water to the water (see, for example, Patent Document 1).

JP 2005-81254 A

  In the reverse osmosis membrane separation device described in Patent Document 1, since the silica concentration of concentrated water is high, it is difficult to accurately detect the silica concentration of concentrated water with a conventional silica concentration sensor having a simple configuration. Therefore, when adjusting the recovery rate, if the concentration of silica in the concentrated water cannot be accurately detected, it is difficult to adjust the silica concentration of the concentrated water, and it is difficult to suppress the precipitation of the silica-based scale.

  Therefore, the present invention can accurately detect the silica concentration value of the concentrated water separated by the reverse osmosis membrane module with a simple configuration, and the recovery rate can be determined based on the silica concentration value of the concentrated water detected accurately. It aims at providing the water treatment apparatus which can adjust and suppress precipitation of a silica type scale.

  The present invention is a water treatment apparatus, wherein a first reverse osmosis membrane module that separates supply water into a first permeated water and a first concentrated water, and a first concentrated water separated by the first reverse osmosis membrane module. And dilution means for mixing the dilution water flowing through the water treatment device to produce first diluted concentrated water, and detecting the silica concentration of the dilution water flowing through the water treatment device as a first detection silica concentration value First silica concentration detection means, second silica concentration detection means for detecting the silica concentration of the first diluted concentrated water produced by the dilution means as a second detection silica concentration value, and the first detection silica concentration value From the second detected silica concentration value, the silica concentration of the first concentrated water separated by the first reverse osmosis membrane module is calculated as the calculated silica concentration value, so that the calculated silica concentration value becomes the allowable silica concentration value. The above A control unit for adjusting the recovery rate is the flow rate ratio of the first permeate to the flow rate of the feed water supplied to the reverse osmosis membrane module, on water treatment apparatus comprising a.

  Moreover, it is preferable that the dilution water which distribute | circulates the inside of the said water treatment apparatus is the 1st permeated water isolate | separated by the said 1st reverse osmosis membrane module.

  The apparatus further comprises a second reverse osmosis membrane module that separates the first permeate separated by the first reverse osmosis membrane module into a second permeate and a second concentrated water, and circulates in the water treatment apparatus. The dilution water is preferably second permeated water separated by the second reverse osmosis membrane module.

  The first permeated water separated by the first reverse osmosis membrane module is further deionized to obtain deionized water and concentrated water, and the dilution water flowing through the water treatment device is: Deionized water obtained by the deionization part is preferable.

  A temperature detecting unit configured to detect a temperature of the supplied water or a temperature of the first concentrated water separated by the first reverse osmosis membrane module as a detected temperature value, and the control unit determines the allowable silica concentration value as the detected temperature; It is preferable to calculate by multiplying the silica solubility of the first concentrated water determined from the value by the safety factor.

  Also, Vc is the sample water amount value of the first concentrated water, Vp is the sample water amount value of the diluted water, Cc is the calculated silica concentration value of the first concentrated water, Cp is the first detected silica concentration value of the diluted water, When Cm is the second detected silica concentration value of the first diluted concentrated water, the control unit calculates the first concentrated water from the calculation formula of Cc = [Cm · (Vc + Vp) −Cp · Vp] / Vc. It is preferable to calculate the calculated silica concentration value Cc.

  The control unit maintains a constant flow rate of the first permeated water separated by the first reverse osmosis membrane module and increases or decreases a flow rate of the first concentrated water separated by the first reverse osmosis membrane module. It is preferable to adjust the recovery rate so that the calculated silica concentration value becomes the allowable silica concentration value.

  The controller maintains a constant flow rate of the first concentrated water separated by the first reverse osmosis membrane module and increases or decreases a flow rate of the first permeated water separated by the first reverse osmosis membrane module. It is preferable to adjust the recovery rate so that the calculated silica concentration value becomes the allowable silica concentration value.

  The dilution means includes a mixing tank in which the first concentrated water and the diluted water separated by the first reverse osmosis membrane module are mixed, and the water pressure of the first concentrated water separated by the first reverse osmosis membrane module. A driving unit that is driven when being introduced into the mixing tank; and a driven unit that is driven by the driving of the driving unit, and generates water pressure toward the mixing tank to generate the first concentrated water. It is preferable to have a driven portion that introduces dilution water having a lower water pressure than the water pressure into the mixing tank.

  The first silica concentration detecting means and the second silica concentration detecting means are preferably constituted by a single silica concentration measuring means capable of switching between two or more different concentration measuring ranges.

  The first reverse osmosis membrane module includes a plurality of submodules, and the plurality of submodules are connected in series so that the concentrated water separated from each of the plurality of submodules is supplied to the next submodule. A third silica concentration detecting means for detecting, as a third detection silica concentration value, a silica concentration of the concentrated water discharged from the sub-module other than the most downstream of the plurality of sub-modules; Preferably, the control unit performs notification by the notification unit when the third detection silica concentration value exceeds a predetermined threshold value.

Moreover, this invention is a water treatment apparatus, Comprising: The 1st reverse osmosis membrane module which isolate | separates supply water into 1st permeated water and 1st concentrated water, and the 1st separated by the said 1st reverse osmosis membrane module Diluted water that circulates in the water treatment device into the deionized part that deionizes the permeated water to obtain deionized water and concentrated water, and the first concentrated water separated by the first reverse osmosis membrane module. A deionizing means for mixing the deionized water to produce a second diluted concentrated water, and a fourth silica concentration for detecting the silica concentration of the second diluted concentrated water produced by the diluting means as a fourth detected silica concentration value Assuming that the silica concentration of the deionized water as the dilution water obtained by the detection means and the deionizing unit is zero, the silica was separated from the fourth detected silica concentration value by the first reverse osmosis membrane module. first calculating the silica concentration of concentrated water The recovery rate is a ratio of the flow rate of the first permeated water to the flow rate of the supplied water supplied to the first reverse osmosis membrane module so that the calculated silica concentration value becomes an allowable silica concentration value. And a control unit that adjusts the water treatment device.

  According to the present invention, the silica concentration value of the concentrated water separated by the reverse osmosis membrane module can be accurately detected with a simple configuration, and the recovery rate can be determined based on the silica concentration value of the concentrated water detected accurately. The water treatment apparatus which can adjust and can suppress precipitation of a silica type scale can be provided.

1 is an overall schematic diagram of a pure water production apparatus 1 according to a first embodiment. It is the front | former part of the whole block diagram of the pure water manufacturing apparatus 1 which concerns on 1st Embodiment. It is the middle stage part of the whole block diagram of the pure water manufacturing apparatus 1 which concerns on 1st Embodiment. It is a back | latter stage part of the whole block diagram of the pure water manufacturing apparatus 1 which concerns on 1st Embodiment. It is a figure which shows the internal structure of RO membrane module 7 of 1st Embodiment. It is a figure which shows the whole structure of silica concentration sensor SS1-SS3B. When the silica concentration of the test water W101 is 0 mgSiO ₂ / L (distilled water), 0.1 mgSiO ₂ / L, and 0.2 mgSiO ₂ / L, the elapsed time from the start of reagent addition and the absorbance of the test water W101 It is a graph which shows a relationship. 1 is an overall schematic diagram of a dilution device 18. FIG. 5 is a flowchart showing a processing procedure when flow rate feedback water amount control is executed in the control unit 30. It is a flowchart which shows the process sequence in the case of performing control which adjusts a collection rate in the control part 30. FIG. 7 is a flowchart showing control in which an alarm is notified when the concentration of concentrated water is high inside the RO membrane module 7 in the control unit 30. It is the whole schematic diagram of the pure water manufacturing apparatus 1A which concerns on 2nd Embodiment. It is a front | former part of the whole block diagram of the pure water manufacturing apparatus 1A which concerns on 2nd Embodiment. It is the middle stage part of the whole block diagram of the pure water manufacturing apparatus 1A which concerns on 2nd Embodiment. It is a back | latter stage part of the whole block diagram of the pure water manufacturing apparatus 1A which concerns on 2nd Embodiment. It is a figure at the time of comprising the 1st silica concentration sensor SS1 and 2nd silica concentration sensor SS2 in 1st Embodiment by the single 5th silica concentration sensor SS5.

Hereinafter, an embodiment when the water treatment apparatus according to the present invention is applied to a pure water production apparatus will be described.
(First embodiment)
First, the pure water manufacturing apparatus 1 which concerns on 1st Embodiment is demonstrated, referring drawings. FIG. 1 is an overall schematic diagram of a pure water production apparatus 1 according to the first embodiment. FIG. 2A is a front part of the overall configuration diagram of the pure water producing apparatus 1 according to the first embodiment. FIG. 2B is a middle part of the entire configuration diagram of the pure water producing apparatus 1 according to the first embodiment. FIG. 2C is a rear part of the entire configuration diagram of the pure water producing apparatus 1 according to the first embodiment. FIG. 3 is a diagram showing an internal structure of the RO membrane module 7 of the first embodiment. FIG. 4 is a diagram illustrating the overall configuration of the silica concentration sensors SS1 to SS3B. FIG. 5 shows the elapsed time from the start of reagent addition and the test water W101 when the silica concentration of the test water W101 is 0 mgSiO ₂ / L (distilled water), 0.1 mgSiO ₂ / L, and 0.2 mgSiO ₂ / L. It is a graph which shows the relationship with a light absorbency. FIG. 6 is an overall schematic diagram of the diluting device 18. The pure water production apparatus 1 according to the present embodiment is applied to, for example, a pure water production apparatus that produces permeated water or deionized water from raw water (for example, tap water). The permeated water and deionized water produced by the pure water production apparatus 1 are sent as pure water to a demand location or the like. In the pure water production apparatus 1 according to the present embodiment, supplying pure water to a demand point or the like is also referred to as “water sampling”.

  As shown in FIG. 1, the pure water production apparatus 1 according to the first embodiment includes a first optional device OP1, a prefilter 4, a second optional device OP2, a pressurizing pump 5, an inverter 6, RO membrane module 7 as 1 reverse osmosis membrane module, decarbonation device 15, first flow path switching valve V71, third optional device OP3, control unit 30, input operation unit 40, and main display unit 60 And comprising.

  The first option device OP1 to the third option device OP3 are devices installed in the pure water production apparatus 1 as optional equipment that can be attached to and detached from the pure water production apparatus 1. The first optional device OP <b> 1 includes a water softener 2 and an activated carbon filter 3. The second optional device OP2 includes a hardness sensor S1 and a residual chlorine sensor S2. The third optional device OP3 includes a second specific resistance sensor RS2, a total organic carbon sensor TOC, and a third temperature sensor TE3.

  Moreover, as shown in FIG. 1, the pure water manufacturing apparatus 1 is provided with the supply water line L1, the permeated water line L21, the RO permeated water return line L41, and the RO concentrated water return line L51. The “line” in the present specification is a general term for lines capable of flowing a fluid such as a flow path, a radial path, and a pipeline.

  2A to 2C, in addition to the configuration shown in FIG. 1, the pure water producing apparatus 1 includes a first on-off valve V11 to a sixth on-off valve V16, a vacuum breaker valve V41, and a pressure reducing valve V42. A supply water supply valve V31, a first drain valve V32 to a third drain valve V34, a first constant flow valve V51 to a fourth constant flow valve V54, and a first check valve V61 to a fourth check valve V64. A first pressure gauge P1 to a third pressure gauge P3, a first pressure sensor PS1 and a second pressure sensor PS2, a pressure switch PSW, a first temperature sensor TE1 to a third temperature sensor TE3, and a first flow sensor. FM1, 1st silica concentration sensor SS1, 2nd silica concentration sensor SS2 to which the dilution apparatus 18 as a dilution means was attached, 1st electrical conductivity sensor EC1, and 2nd specific resistance sensor RS2 are provided.

  In FIG. 1 and FIG. 2A to FIG. 2C, the electrical connection path is omitted, but the control unit 30 is configured to supply water supply valve V31, first flow path switching valve V71, first drain valve V32 to third drain valve. V34, pressure switch PSW, first temperature sensor TE1 to third temperature sensor TE3, first pressure sensor PS1 and second pressure sensor PS2, first flow sensor FM1, first conductivity sensor EC1, second specific resistance sensor RS2. , The total organic carbon sensor TOC, the hardness sensor S1, the residual chlorine sensor S2, the first silica concentration sensor SS1, the second silica concentration sensor SS2, and the like.

  First, the front part of the overall configuration diagram in the pure water production apparatus 1 will be described.

  As shown in FIGS. 1 and 2A, the supply water W1 flows through the supply water line L1. The supply water line L1 is a line through which the supply water W1 is circulated to the RO membrane module 7. The supply water line L1 includes a first supply water line L11 and a second supply water line L12.

  The raw water W11 (supply water W1) flows through the first supply water line L11. The first supply water line L11 is a line that connects a supply source (not shown) of the raw water W11 and the water softener 2. The upstream end of the first supply water line L11 is connected to a supply source (not shown) of the raw water W11. Further, the downstream end of the first supply water line L <b> 11 is connected to the water softener 2.

  As shown in FIG. 2A, the first supply water line L11 is provided with a connecting portion J1, a first on-off valve V11, and a water softener 2 in order from the upstream side. The first on-off valve V11 is a manual valve that can be operated to open and close the first supply water line L11.

  The water softener 2 is an apparatus that manufactures the soft water W12 (feed water W1) by replacing the hardness component contained in the raw water W11 with sodium ions. The water softener 2 has an ion exchange tower containing a cation exchange resin bed in a pressure tank.

  Soft water W12 (supply water W1) flows through the second supply water line L12. The second supply water line L12 is a line through which the soft water W12 is circulated to the RO membrane module 7. The second supply water line L <b> 12 is a line that connects the water softener 2 and the RO membrane module 7. As shown in FIG. 2A, the upstream end of the second supply water line L <b> 12 is connected to the water softener 2. As shown in FIG. 2B, the downstream end of the second supply water line L12 is connected to the primary inlet port (inlet for the supply water W1) of the RO membrane module 7.

  As shown in FIG. 2A, in order from the upstream side, the second on-off valve V12, the connecting portion J2, the third on-off valve V13, the activated carbon filter 3, the fourth on-off valve V14, and the connecting portion are connected to the second supply water line L12. J3, the prefilter 4, the connection part J4, and the connection part J5 are provided. Further, after the connecting portion J5, as shown in FIG. 2B, as shown in FIG. 2B, the fifth on-off valve V15, the connecting portion J6, the pressure reducing valve V42, the supply water replenishing valve V31, the connecting portion J51, the connecting portion J7, the connecting portion J8, A pump 5, a connection portion J9, and an RO membrane module 7 are provided. The second on-off valve V12 to the fifth on-off valve V15 are manual valves that can be operated to open and close the second supply water line L12. The supply water supply valve V31 is an automatic valve that can control the opening and closing of the second supply water line L12. The supply water supply valve V31 is electrically connected to the control unit 30. The opening and closing of the supply water replenishing valve V31 is controlled by a flow path opening / closing signal transmitted from the control unit 30.

  The activated carbon filter 3 is a device that removes chlorine components (mainly free residual chlorine) contained in the soft water W12 (feed water W1). The activated carbon filter 3 has a filtration tower in which a filter medium bed made of activated carbon is housed in a pressure tank. The activated carbon filter 3 purifies the soft water W12 (feed water W1) by decomposing and removing the chlorine component contained in the soft water W12, adsorbing and removing organic components, and capturing suspended substances.

  The prefilter 4 is a filter that removes fine particles contained in the soft water W12 (supply water W1) purified by the activated carbon filter 3. The prefilter 4 is configured by accommodating a filter element in a housing. As the filter element, for example, a nonwoven fabric filter element or a thread-wound filter element having a filtration accuracy of 1 to 50 μm is used.

  The hardness sensor S1 is a device that measures the total hardness (that is, the hardness leak amount) of the supply water W1 flowing through the supply water line L1. The residual chlorine sensor S2 is a device that measures the free residual chlorine concentration (that is, chlorine leak amount) of the supply water W1 flowing through the supply water line L1. As shown in FIG. 2A, the hardness sensor S1 and the residual chlorine sensor S2 are connected to the supply water line L1 at the connection portion J5 via the measurement line L110. The connecting part J5 is disposed between the prefilter 4 and the fifth on-off valve V15 in the supply water line L1. The hardness sensor S1 and the residual chlorine sensor S2 are electrically connected to the control unit 30. The hardness leak amount measured by the hardness sensor S1 and the chlorine leak amount measured by the residual chlorine sensor S2 are transmitted to the control unit 30 as detection signals, respectively. Note that an upstream end portion of a soft water supply line L24 described later is connected to the connecting portion J5.

Next, the middle part of the overall configuration diagram in the pure water production apparatus 1 will be described.
As shown in FIG. 2B, a vacuum breaker valve V41 is connected to the connecting portion J6. The vacuum breaker valve V41 is a normally closed pressure operating valve, and when the pressure in the supply water line L1 becomes lower than the atmospheric pressure, the valve opens to suck the atmosphere. By providing the vacuum breaker valve V41, even if the raw water W11 (feed water W1) is cut off and the feed water line L1 becomes negative pressure, it is possible to prevent problems such as damage to the membrane of the RO membrane module 7. it can.

  The pressure reducing valve V42 is a device that adjusts the pressure of the soft water W12 that has passed through the water softener 2, the activated carbon filter 3, and the prefilter 4 to a pressure lower than the pressure of the concentrated water W3 flowing out from the RO membrane module 7. The pressure reducing valve V42 adjusts the pressure of the soft water W12 so that the pressure of the concentrated water W3 is larger than the pressure of the soft water W12 (pressure of the soft water W12 <pressure of the concentrated water W3). Thereby, a part of the concentrated water W3 is circulated to the soft water W12, and the supply water in which the concentrated water W3 is mixed with the soft water W12 is supplied to the RO membrane module 7. That is, in the RO membrane module 7, a cross-flow type separation operation for producing permeated water is performed while circulating the supply water by the pressure pump 5.

  The pressurizing pump 5 is a device that sucks in the supply water W1 flowing through the supply water line L1 and pumps (discharges) it toward the RO membrane module 7. The pressurizing pump 5 is supplied with driving power whose frequency is converted from the inverter 6. The pressurizing pump 5 is driven at a rotational speed corresponding to the frequency of the supplied driving power (hereinafter also referred to as “driving frequency”).

  The inverter 6 is an electric circuit (or a device having the circuit) that supplies driving power whose frequency is converted to the pressure pump 5. The inverter 6 is electrically connected to the control unit 30. A frequency designation signal is input to the inverter 6 from the control unit 30. The inverter 6 outputs driving power having a driving frequency corresponding to the frequency designation signal (current value signal or voltage value signal) input by the control unit 30 to the pressurizing pump 5.

  The RO membrane module 7 uses supply water W1 pumped by the pressurization pump 5 as permeate water W2 from which dissolved salts have been removed (first permeate) and concentrated water W3 from which dissolved salts have been concentrated (first concentrate water). ) And separated. The RO membrane module 7 is configured by accommodating a single or a plurality of spiral RO membrane elements in a pressure vessel (vessel). Examples of the RO membrane used for the RO membrane element include a crosslinked aromatic polyamide composite membrane. Examples of RO membrane elements composed of a crosslinked aromatic polyamide composite membrane include: Toray Industries, Inc .: model name “TMG20-400”, Eunjin Chemical Co., Ltd .: model name: “RE8040-BLF”, Nitto Denko Corporation: model name: “ESPA1” Are commercially available, and these elements can be suitably used.

  Here, the internal configuration of the RO membrane module 7 will be described. In the present embodiment, the RO membrane module 7 has three submodules 71, 72, and 73 as shown in FIG. 3 in order to increase the production water volume of the separation treated water (permeated water). The three submodules 71, 72, 73 are connected in series so that the module concentrated water W151, W152, W153 separated from each of the three submodules 71, 72, 73 is supplied to the next submodule. The three submodules 71, 72, 73 are configured by connecting a first submodule 71, a second submodule 72, and a third submodule 73 in order from the upstream side to the downstream side. Each of the three submodules 71, 72, 73 contains the RO membrane element in a pressure vessel (vessel).

  As shown in FIG. 3, the RO membrane module 7 has a plurality of lines connecting the three sub modules 71, 72, 73 therein. The RO membrane module 7 includes a module introduction line L81, a first module permeate water line L821, a second module permeate water line L822, a third module permeate water line L823, a module permeate water outlet line L83, and a first module. A concentrated water line L841, a second module concentrated water line L842, and a module concentrated water outlet line L85 are provided. The RO membrane module 7 includes therein a 3A silica concentration sensor SS3A as third silica concentration detection means and a 3B silica concentration sensor SS3B as third silica concentration detection means.

  The module introduction line L81 is a line that connects the downstream end of the second supply water line L12 connected to the primary inlet port of the RO membrane module 7 and the primary inlet port of the first submodule 71. The first module permeate line L821 is a line that connects the secondary side outlet port of the first submodule 71 and the connection portion J81. The second module permeated water line L822 is a line that connects the secondary side outlet port of the second submodule 72 and the connecting portion J81. The third module permeated water line L823 is a line that connects the secondary side outlet port of the third submodule 73 and the connection portion J82. The module permeated water lead-out line L83 is a line that connects the connecting part J81, the connecting part J82, and the upstream end of the permeated water line L21 connected to the primary outlet port of the RO membrane module 7.

  The first module concentrated water line L841 is a line that connects the primary side outlet port of the first submodule 71 and the primary side inlet port of the second submodule 72. The second module concentrated water line L842 is a line that connects the primary side outlet port of the second submodule 72 and the primary side inlet port of the third submodule 73. The module concentrated water outlet line L85 is a line connecting the primary side outlet port of the third submodule 73 and the downstream end of the RO concentrated water return line L51 connected to the primary side outlet port of the RO membrane module 7. .

  The supply water W1 supplied to the RO membrane module 7 is supplied to the first submodule 71 as the submodule supply water W13 through the module introduction line L81. The first submodule 71 separates the submodule supply water W13 into a first module permeated water W141 and a first module concentrated water W151.

  The first module concentrated water W151 separated by the first submodule 71 is supplied to the second submodule 72 through the first module concentrated water line L841. The second submodule 72 separates the first module concentrated water W151 separated by the first submodule 71 into a second module permeated water W142 and a second module concentrated water W152.

The third module concentrated water W152 separated by the second submodule 72 is supplied to the third submodule 73 through the second module concentrated water line L842. The third submodule 73 separates the second module concentrated water W152 into a third module permeated water W143 and a third module concentrated water W153.
The third module concentrated water W153 separated by the third submodule 73 passes through the module concentrated water lead-out line L85, and is supplied from the primary outlet port (the outlet of the concentrated water W3) to the RO membrane module 7 as the concentrated water W3. It is discharged outside.

  Further, the first module permeated water W141 separated by the first submodule 71, the second module permeated water W142 separated by the second submodule 72, and the third module permeated water W143 separated by the third submodule 73. The secondary membrane outlet port (permeation) of the RO membrane module 7 passes through the module permeate outlet line L83 via the first module permeate line L821, the second module permeate line L822, and the third module permeate line L823. From the outlet of the water W2, the permeated water W2 is discharged to the outside of the RO membrane module 7.

  In the RO membrane module 7 configured as described above, the first module permeated water W141 to the third module permeated water W143 separated by the three submodules 71, 72, and 73 are transmitted to the permeated water line L21 as permeated water W2. The third module concentrated water W153 at the most downstream side that has been discharged and sequentially separated by the first sub-module 71, the second sub-module 72, and the third sub-module 73 connected in series is used as the concentrated water W3 for the RO concentrated water return line. Discharge to L51.

Again, another configuration in the middle part of the entire configuration diagram of the pure water production apparatus 1 will be described.
As shown in FIG. 2B, the RO concentrated water return line L51 is a line for returning a part W31 of the concentrated water W3 separated by the RO membrane module 7 to the supply water line L1. The upstream end of the RO concentrated water return line L51 is connected to the primary outlet port (the outlet of the concentrated water W3) of the RO membrane module 7. The downstream end of the RO concentrated water return line L51 is connected to the supply water line L1 at the connection J51. The RO concentrated water return line L51 is provided with a first check valve V61 and a first constant flow valve V51.

  The RO concentrated water discharge line L61 is a line for discharging the remaining portion W32 of the concentrated water W3 separated by the RO membrane module 7 from the middle of the RO concentrated water return line L51 to the outside of the apparatus. The upstream end portion of the RO concentrated water discharge line L61 is connected to the connection portion J53. The connecting portion J53 is disposed between the RO membrane module 7 and the connecting portion J52 in the RO concentrated water return line L51. The upstream end portions of the first concentrated water drain line L611, the second concentrated water drain line L612, and the third concentrated water drain line L613 are connected to the RO concentrated water discharge line L61 at the connecting portions J55 and J56.

  The first concentrated water drain line L611 to the third concentrated water drain line L613 are provided with a first drain valve V32 to a third drain valve V34, and a second constant flow valve V52 to a fourth constant flow valve V54, respectively. Yes. The second constant flow valve V52 to the fourth constant flow valve V54 are set to different flow values. The first drainage valve V32 to the third drainage valve V34 can individually open and close the first concentrated water drainage line L611 to the third concentrated water drainage line L613. By appropriately selecting the number of the first drain valve V32 to the third drain valve V34 that are opened, the drainage flow rate of the concentrated water W3 discharged to the outside of the apparatus can be adjusted. By this adjustment, the recovery rate of the permeated water W2 can be maintained at a preset value. The recovery rate of the permeated water W2 is the ratio (%) of the permeated water W2 to the flow rate of the soft water W12 supplied to the RO membrane module 7 (the supplied water W1 before the part W31 of the concentrated water W3 is mixed). Say.

  The first drain valve V32 to the third drain valve V34 are electrically connected to the control unit 30, respectively. Opening and closing of the first drain valve V32 to the third drain valve V34 is controlled by a drive signal transmitted from the control unit 30.

  The downstream ends of the first concentrated water drainage line L611, the second concentrated water drainage line L612, and the third concentrated water drainage line L613 are connected to the upstream end of the merged drainage line L62 at the connecting portions J57 and J58. Has been. The downstream end portion of the combined drainage line L62 is connected or opened to a drainage pit (not shown), for example. A second check valve V62 is provided in the middle of the combined drainage line L62.

  The permeated water line L <b> 21 is a line through which the permeated water W <b> 2 separated by the RO membrane module 7 is circulated to the decarbonation device 15. As shown in FIGS. 2B and 2C, the permeate water line L21 includes a front-stage permeate water line L211 and a middle-stage permeate water line L212.

  As shown in FIG. 2B, the upstream end of the front-stage permeate line L211 is connected to the secondary port (the outlet of the permeate W2) of the RO membrane module 7. As shown in FIG. 2C, the downstream end of the front-stage permeate line L211 is connected to the middle-stage permeate line L212 and the RO permeate return line L41 via the first flow path switching valve V71. .

  As shown in FIG. 2B, the upstream side permeate line L211 is provided with a third check valve V63, a connection portion J10, a connection portion J11, a connection portion J63, and a sixth on-off valve V16 in order from the upstream side. Yes. Further, after the sixth on-off valve V16, as shown in FIG. 2C, a decarboxylation device 15, a connection portion J31, a connection portion J32, and a first flow path switching valve V71 are provided. The sixth on-off valve V16 is a manual valve that can be operated to open and close the permeate line L21.

Next, the latter part of the entire configuration diagram in the pure water production apparatus 1 will be described.
In FIG. 2C, the decarboxylation device 15 is equipment for producing decarbonated water as purified water by degassing the free carbonic acid (dissolved carbon dioxide gas) contained in the permeated water W2 with a gas separation membrane module. By providing the decarboxylation device 15 on the downstream side of the RO membrane module 7, free carbon dioxide that easily permeates the RO membrane can be removed from the permeated water W <b> 2. Accordingly, it is possible to obtain the permeated water W2 having a higher purity. In the present embodiment, the decarbonated water produced by the decarboxylation device 15 is also referred to as permeate W2 for convenience.

  In the decarboxylation device 15 of this embodiment, an external perfusion-type gas separation membrane module composed of a hollow fiber membrane is used, and a sweep gas such as air is introduced while suctioning the inside of the hollow fiber membrane with a vacuum pump (described later). Then, free carbon dioxide is exhausted while being transferred into the sweep gas through the membrane wall. As a gas separation membrane module suitable for such an application, for example, a product name “Liqui-Cel G-521R” manufactured by Celgard Co., Ltd. may be mentioned. The vacuum pump connected to the gas separation membrane module is electrically connected to the control unit 30.

  The soft water supply line L24 is a line that supplies a part of the soft water W12 (supply water W1) flowing through the second supply water line L12 (see FIG. 2A) to the decarboxylation device 15 (sealed water tank). The upstream end of the soft water supply line L24 is connected to the connection portion J5 (see FIG. 2A) of the second supply water line L12. The downstream end of the soft water supply line L24 is connected to the gas phase part (upper part) of the sealed water tank. A part of the soft water W12 (supply water W1) flowing through the second supply water line L12 is supplied to the decarboxylation device 15 via the soft water supply line L24, whereby the second supply water line L12 (see FIG. 2A) is supplied. A part of the circulated soft water W12 (supply water W1) is used as sealed water for the vacuum pump, and is then discharged out of the apparatus via a sealed water discharge line L71 (described later).

  As shown in FIG. 2C, the first flow path switching valve V71 is a flow path (water sampling side flow path) through which the permeated water W2 separated by the RO membrane module 7 is circulated through the middle stage permeated water line L212. Or it is an automatic valve which can be switched to the flow path (circulation side flow path) which distribute | circulates toward the supply water line L1 of the upstream of the RO membrane module 7 via the RO permeate return line L41. The first flow path switching valve V71 is configured by, for example, an electric or electromagnetic three-way valve. The first flow path switching valve V71 is electrically connected to the control unit 30. The switching of the flow path in the first flow path switching valve V71 is controlled by a flow path switching signal transmitted from the control unit 30.

  The RO permeated water return line L41 is a line that returns the permeated water W2 separated by the RO membrane module 7 to the supply water line L1 upstream of the RO membrane module 7. The upstream end of the RO permeate return line L41 is connected to the first flow path switching valve V71. As shown in FIG. 2B, the downstream end of the RO permeate return line L41 is connected to the RO concentrated water return line L51 at the connection portion J52. The connection part J52 is arrange | positioned between the connection part J53 and the connection part J51 in RO concentrated water return line L51. The portion from the connecting portion J52 to the connecting portion J51 in the RO permeate return line L41 is common to the portion from the connecting portion J52 to the connecting portion J51 in the RO concentrated water return line L51. A fourth check valve V64 is provided on the upstream side of the RO permeate return line L41 as shown in FIG. 2C.

  The middle-stage permeated water line L212 is a line for sending the permeated water W2 separated by the RO membrane module 7 as pure water toward the demand point. The upstream end of the middle permeate line L212 is connected to the first flow path switching valve V71. The downstream end of the middle-stage permeate line L212 is connected to a demand point device or the like (not shown).

  The sealed water discharge line L71 is a line for discharging the sealed water drainage W8 discharged from the decarboxylation device 15 to the outside of the device. The upstream end of the sealed water discharge line L71 is connected to the decarbonation device 15. The downstream side of the sealed water discharge line L71 is connected or opened to a drainage pit (not shown), for example.

  The first pressure gauge P1 to the fourth pressure gauge P4 are devices that measure the pressure of water flowing through each connected line. As shown in FIG. 2A, the first pressure gauge P1 to the fourth pressure gauge P4 are each connected to the supply water line L1 at the connection portions J1 to J4.

  The first pressure sensor PS1 and the second pressure sensor PS2 are devices that measure the pressure of water flowing through each connected line. As shown in FIG. 2B, the first pressure sensor PS1 is connected to the supply water line L1 at the connection portion J9. The connecting portion J9 is disposed between the pressurizing pump 5 and the RO membrane module 7 in the supply water line L1. The second pressure sensor PS2 is connected to the permeate line L21 at the connection portion J11. The connecting portion J11 is disposed between the RO membrane module 7 and the decarboxylation device 15 in the permeate line L21.

  The first pressure sensor PS1 and the second pressure sensor PS2 are electrically connected to the control unit 30. The pressure of the supply water W1 or the permeate water W2 measured by the first pressure sensor PS1 and the second pressure sensor PS2 is transmitted to the control unit 30 as a detection signal.

  The pressure switch PSW is a device that detects that the pressure of the supply water W1 flowing through the supply water line L1 is equal to or lower than the first set pressure value or equal to or higher than the second set pressure value. As shown in FIG. 2B, the pressure switch PSW is connected to the supply water line L1 at the connection portion J7. The connection part J7 is arrange | positioned between the connection part J51 and the pressurization pump 5 in the supply water line L1. A detection signal of the pressure of the supply water W <b> 1 detected by the pressure switch PSW is transmitted to the control unit 30.

  The first temperature sensor TE1 to the third temperature sensor TE3 are devices that measure the temperature of water flowing through each connected line. The first temperature sensor TE1 is connected to the supply water line L1 at the connection portion J8. The connection part J8 is arrange | positioned between the connection part J51 and the pressurization pump 5 in the supply water line L1. The second temperature sensor TE2 as the water temperature detecting means is connected to the permeated water line L21 at the connection portion J31. The connection part J31 is arrange | positioned between the decarbonation apparatus 15 and the 1st flow-path switching valve V71 in the permeated water line L21. The third temperature sensor TE3 is connected to the middle-stage permeated water line L212 at the connection portion J43. The connection part J43 is arrange | positioned at the middle stage side permeated water line L212.

  The first temperature sensor TE1 to the third temperature sensor TE3 are electrically connected to the control unit 30. The temperature (detected temperature value) of the supply water W1 and the permeated water W2 (desalted water W6 in other embodiments described later) measured by the first temperature sensor TE1 to the third temperature sensor TE3 is sent to the control unit 30 as a detection signal. Sent.

  The first flow rate sensor FM1 is a device that measures the flow rate of the permeated water W2 that flows through the connected permeated water line L21. The first flow rate sensor FM1 is connected to the permeate line L21 at the connection portion J10. The connection part J10 is arrange | positioned between the RO membrane module 7 and the decarbonation apparatus 15 in the permeated water line L21.

  The first flow sensor FM1 is electrically connected to the control unit 30. The flow rate (detected flow rate value) of the permeated water W2 measured by the first flow rate sensor FM1 is transmitted to the control unit 30 as a detection signal.

  The first electrical conductivity sensor EC1 is a device that measures the electrical conductivity (electrical characteristic value) of the permeated water W2 flowing through the permeated water line L21. The first electrical conductivity sensor EC1 is connected to the permeated water line L21 at the connection portion J32. The connection part J32 is arrange | positioned between the decarboxylation apparatus 15 and the 1st flow-path switching valve V71 in the permeated water line L21.

  2nd specific resistance sensor RS2 is an apparatus which measures the specific resistance (electrical characteristic value) of the permeated water W2 which distribute | circulates the middle stage side permeated water line L212. The second specific resistance sensor RS2 is connected to the middle-stage permeated water line L212 at the connection portion J41. The connecting portion J41 is disposed downstream of the first flow path switching valve V71 in the middle-stage permeated water line L212. Note that the second specific resistance sensor RS2 has a built-in temperature sensor for temperature compensation of the measured specific resistance value. Therefore, the second specific resistance sensor RS2 can measure the water temperature of the permeated water W2.

  The first electrical conductivity sensor EC1 and the second specific resistance sensor RS2 are electrically connected to the control unit 30. The electrical conductivity of the permeated water W2 measured by the first electrical conductivity sensor EC1 and the specific resistance (and temperature) of the permeated water W2 measured by the second specific resistance sensor RS2 are detected signals to the control unit 30, respectively. As sent.

  The total organic carbon sensor TOC is a device that detects the amount of organic carbon in the permeated water W2 flowing through the middle permeate water line L212. Organic carbon is carbon in organic matter present in water. The total organic carbon sensor TOC is connected to the middle-stage permeated water line L212 at the connection portion J42. The connecting portion J42 is disposed on the downstream side of the first flow path switching valve V71 in the middle-stage permeated water line L212.

  The all organic carbon sensor TOC is electrically connected to the control unit 30. The total organic carbon amount of the permeated water W2 detected by the total organic carbon sensor TOC is transmitted to the control unit 30 as a detection signal.

The first silica concentration sensor SS1 is a device that detects the silica concentration of the permeated water W2 flowing through the permeate water line L21 as the first detection silica concentration value Cp. As shown in FIG. 2B, the first silica concentration sensor SS1 is connected to the permeated water line L21 at the connecting portion J63 via the permeated water introduction line L112. The connecting part J63 is disposed between the RO membrane module 7 and the decarboxylation device 15 in the permeate line L21.
The second silica concentration sensor SS2 is attached to a diluting device 18 described later. The second silica concentration sensor SS2 is a device that detects the silica concentration of the diluted concentrated water (first diluted concentrated water) W30 diluted (manufactured) by the diluting device 18 as the second detected silica concentration value Cm. The configuration of the dilution device 18 will be described later.

As shown in FIG. 3, the third A silica concentration sensor SS3A is a device that detects the silica concentration of the first module concentrated water W151 flowing through the first module concentrated water line L841 as the third A detected silica concentration value Cq. The third A silica concentration sensor SS3A is connected to the first module concentrated water line L841 at the connection portion J83 inside the RO membrane module 7. The connection part J83 is arrange | positioned in the middle of the 1st module concentrated water line L841.
The third B silica concentration sensor SS3B is a device that detects the silica concentration of the second module concentrated water W152 flowing through the second module concentrated water line L842 as the third B detected silica concentration value Cr. The third B silica concentration sensor SS3B is connected to the second module concentrated water line L842 at the connection portion J84 inside the RO membrane module 7. The connection part J84 is arrange | positioned in the middle of the 2nd module concentrated water line L842.

  The first silica concentration sensor SS1 to the third B silica concentration sensor SS3B are electrically connected to the control unit 30. The detected silica concentration values of the permeated water W2, the diluted concentrated water W30, the first module concentrated water W151, and the second module concentrated water W152 detected by the first silica concentration sensor SS1 to the third B silica concentration sensor SS3B are sent to the control unit 30. It is transmitted as a detection signal.

  Here, the structure of the first silica concentration sensor SS1 to the third B silica concentration sensor SS3B will be described. The first silica concentration sensor SS1 to the third B silica concentration sensor SS3B are devices that measure the silica concentration of the inspection water W101 by the molybdenum yellow method (molybdenum yellow absorptiometry). Here, for convenience of explanation, water (permeated water W2, diluted concentrated water W30, first module concentrated water W151, second module concentrated water W152, etc.) measured by silica concentration sensors SS1 to SS3B will be described as test water W101.

  The first silica concentration sensor SS1 to the third B silica concentration sensor SS3B can measure the low concentration silica concentration and the high concentration silica concentration by switching the measurement wavelength. As shown in FIG. 4, the silica concentration sensors SS1 to SS3B include a measurement cell 120, a reagent injection unit 130, an optical detection unit 140 that constitutes a part of the absorbance measurement unit, a stirring unit 150, and a sensor display unit 160. And a sensor control unit 110, a test water introduction line L101, and a test water discharge line L102.

  The measurement cell 120 is a container that stores the inspection water W101 for measuring the silica concentration. The measurement cell 120 is made of an opaque resin material. The measurement cell 120 has a pair of light transmission windows 121 and 122 formed on the side wall thereof. Transparent plates 121a and 122a are fitted into the light transmission windows 121 and 122, respectively.

  The inspection water introduction line L101 is a line for introducing the inspection water W101 into the measurement cell 120. As shown in FIG. 4, the inspection water introduction line L <b> 101 is connected to the side wall below the light transmission windows 121 and 122 of the measurement cell 120. The inspection water introduction line L101 is a flow path for introducing the inspection water W101 into the measurement cell 120. An electromagnetic valve 123 is provided in the inspection water introduction line L101. The electromagnetic valve 123 is a valve used when collecting the inspection water W101. The opening and closing of the electromagnetic valve 123 is controlled by a drive signal output from the sensor control unit 110.

  The inspection water discharge line L102 is a line for discharging the inspection water W101 (including the reagent W102) from the measurement cell 120. As shown in FIG. 4, the inspection water discharge line L <b> 102 is connected to the side wall above the light transmission windows 121 and 122 of the measurement cell 120. The inspection water discharge line L102 is a flow path for discharging the inspection water W101 from the measurement cell 120.

  The reagent injection unit 130 is a facility for injecting the reagent W102 into the measurement cell 120. The reagent injection unit 130 holds the reagent W102 therein, and discharges and supplies a desired amount of the reagent W102 into the measurement cell 120. The reagent W102 is mixed with a coloring substance that develops color by reacting with silica contained in the test water W101. In this embodiment, the silica concentration is measured by the molybdenum yellow method, and an aqueous solution containing hexaammonium heptamolybdate and an inorganic acid is used as the reagent. Since the composition of the one-component reagent aqueous solution suitable for this embodiment is disclosed in detail in Japanese Patent No. 5169809 by the applicant of the present application, the detailed description is omitted by citing the patent document.

  The reagent injection unit 130 includes a reagent cartridge 131 and a roller pump mechanism 132. The reagent cartridge 131 is an injection body comprising a reagent pack (not shown) filled with the reagent W102 (the above-described one-component reagent aqueous solution), and an elastic tube having one end connected to the reagent pack and a nozzle at the other end. (Not shown).

  As shown in FIG. 4, the roller pump mechanism 132 is provided above the measurement cell 120. A cartridge insertion port 133 is provided at the upper part of the roller pump mechanism 132. The reagent cartridge 131 is detachably attached to the cartridge insertion port 133.

  The roller pump mechanism 132 includes a roller pump 134. By driving the roller pump 134 and squeezing the elastic tube of the injection body accommodated in the reagent cartridge 131, the reagent W102 in the reagent pack can be injected from the nozzle toward the measurement cell 120. The driving of the roller pump 134 is controlled by a driving signal output from the sensor control unit 110.

  The optical detection unit 140 is a facility for measuring the absorbance of the test water W101 stirred together with the reagent W102. As shown in FIG. 4, the optical detection unit 140 includes a first light emitting element 141, a second light emitting element 142, a light emitting substrate 143, a first light receiving element 144, a second light receiving element 145, and a light receiving substrate 146. .

The first light emitting element 141 and the second light emitting element 142 are mounted on the light emitting substrate 143. The first light emitting element 141 and the second light emitting element 142 are elements that irradiate light toward the light transmission window 121 of the measurement cell 120. The 1st light emitting element 141 and the 2nd light emitting element 142 are comprised by LED (light emitting diode) from which light emission wavelength differs, respectively. In the present embodiment, the first light emitting element 141 is a light emitting element that can emit light having a wavelength of 375 nm (low concentration measurement wavelength) in order to measure a low concentration of silica. The second light emitting element 142 is a light emitting element capable of emitting light having a wavelength of 450 nm (high concentration measurement wavelength) in order to measure a high concentration of silica.
The turning on / off of the first light emitting element 141 and the second light emitting element 142 is controlled by a drive signal output from the sensor control unit 110.

  The first light receiving element 144 and the second light receiving element 145 are mounted on the light receiving substrate 146. The first light receiving element 144 and the second light receiving element 145 are elements that receive the transmitted light that has passed through the light transmitting window 122 of the measurement cell 120. The first light receiving element 144 and the second light receiving element 145 are configured by phototransistors. The first light receiving element 144 and the second light receiving element 145 output a detection value signal corresponding to the received transmitted light amount to the sensor control unit 110.

  The stirring unit 150 is a facility for stirring the test water W101 and the reagent W102 accommodated in the measurement cell 120. As shown in FIG. 4, the stirring unit 150 is provided at the bottom of the measurement cell 120. The stirring unit 150 includes a stirring bar 151 and a stator coil 152. The stirrer 151 is rotatably disposed at the bottom of the measurement cell 120. The stator coil 152 is an electromagnetic induction coil formed in a ring shape so as to surround the periphery of the measurement cell 120. When a drive current is supplied to the stator coil 152, the stirrer 151 disposed at the bottom of the measurement cell 120 rotates in a non-contact manner due to the action of electromagnetic induction. The operation of the stator coil 152 is controlled by a drive current supplied from the sensor control unit 110.

  The sensor display unit 160 is a device that displays the measured value of the silica concentration of the measured inspection water W101, the operation status of the silica concentration sensors SS1 to SS3B, and the like. The sensor display unit 160 is configured by a liquid crystal display panel.

  The sensor control unit 110 is a device that controls the operation of the silica concentration sensors SS1 to SS3B. The sensor control unit 110 controls the first light emitting element 141 and the second light emitting element 142. The sensor control unit 110 receives outputs from the first light receiving element 144 and the second light receiving element 145. The sensor control unit 110 measures the concentration of the silica component contained in the inspection water W101 based on the absorbance detected by the optical detection unit 140. The sensor control unit 110 causes the sensor display unit 160 to display the measured value of the silica concentration of the measured inspection water W101. The sensor control unit 110 stores a later-described calibration curve in an internal memory for each measurement wavelength.

  In order to measure the low-concentration silica concentration, the sensor control unit 110 includes an absorbance calculation unit 111, a change amount calculation unit 112, a timing unit 113, and a silica concentration detection unit 114 that constitute a part of the absorbance measurement unit. Have.

  The absorbance calculation unit 111 calculates the absorbance of the test water W101 at the first time T1 and the second time T2 (see FIG. 5) based on the detected value of the transmitted light amount detected by the optical detection unit 140. Thereby, in this embodiment, the optical detection unit 140 and the absorbance calculation unit 111 measure the absorbance at 375 nm in the test water W101 to which the reagent W102 is added.

  The first time T1 is a time immediately after the reagent W102 is added (see FIG. 5). The first time T1 is preferably within 3 minutes after the reagent W102 is added to the test water W101. The first time T1 is within a range in which the addition of the specified amount of the reagent W102 can be performed, and a time close to immediately after the addition of the specified amount of the reagent W102 is completed. In the present embodiment, the first time T1 is about 2 minutes (see FIG. 5). When the time required for the addition operation of the reagent W102 is extremely short, the first time T1 may be 0 minutes, which is the same as the time when the reagent W102 is added to the test water W101.

  The second time T2 is a reagent reaction end time when the reaction between the test water W101 and the reagent W102 is completed (see FIG. 5). The second time T2 is a time during which the color reaction between the test water W101 and the reagent W102 is almost completed and the coloration of the test water W101 is stabilized. 110 memory (not shown). In the present embodiment, the second time T2 is about 20 minutes after the addition of the reagent W102 is started (see FIG. 5).

  The timer 113 measures the second time T2. At the second time T2 timed by the time measuring unit 113, the absorbance calculation unit 111 calculates the absorbance of the test water W101.

  For the absorbance of the test water W101 to which the reagent W102, which is measured by the optical detection unit 140 and the absorbance calculation unit 111, is added, the change amount calculation unit 112 is the test water W101 after the first time T1 has elapsed since the reagent W102 was added. And the difference A2-A1 between the absorbance A1 and the absorbance A2 of the test water W101 after a second time T2 longer than the first time T1 from the addition of the reagent W102 is calculated.

  The silica concentration detection unit 114 detects the silica concentration based on the change amount (difference) in absorbance calculated by the change amount calculation unit 112. Specifically, the silica concentration detection unit 114 regards the calculated change (difference) in absorbance as the absorbance of the test water W101, and performs an inspection using a calibration curve between the silica concentration and the absorbance for this absorbance. The silica concentration in the water W101 is determined. The calibration curve is created in advance as a relation line between the silica concentration and the absorbance using a silica standard solution, and is stored in a memory (not shown) of the sensor control unit 110. In the present embodiment, a calibration curve created in a state where the color reaction between the test water W101 and the reagent W102 is completed as a calibration curve between the absorbance of the test water W101 and the silica concentration in the memory (not shown). Is remembered.

The first silica concentration sensor SS1 to the third B silica concentration sensor SS3B configured as described above are capable of measuring the silica concentration (10 to 80 mg SiO ₂ / L) of the high concentration silica by switching the measurement wavelength. It is possible to switch between the range and the low concentration range in which the silica concentration of the low concentration silica (0.1 to ₁ mg SiO ₂ / L) can be measured. In the present embodiment, the first silica concentration sensor SS1 is used in a low concentration range in order to detect the silica concentration of the permeated water W2. The second silica concentration sensor SS2 detects the silica concentration of the diluted concentrated water W30 produced by the diluting device 18 described later, and the silica concentration of the diluted concentrated water W30 can be detected in a high concentration range. Used in the concentration range.

Next, the diluting device 18 will be described.
As shown in FIGS. 2B and 6, the dilution device 18 is attached to the second silica concentration sensor SS2. The dilution device 18 is a device for diluting the concentrated water W3 to be detected by the second silica concentration sensor SS2 in order to accurately detect the silica concentration in the second silica concentration sensor SS2. The diluting device 18 mixes the concentrated water W3 separated by the RO membrane module 7 and the permeated water W2 (diluted water) flowing through the pure water production apparatus 1 to obtain the diluted concentrated water W30 (first diluted concentrated water). Manufacturing. In this way, the diluting device 18 dilutes the concentrated water W3 separated by the RO membrane module 7 using the permeated water W2 separated by the RO membrane module 7 as dilution water. The dilution device 18 of the present embodiment has a mechanical configuration, and is configured to mix the concentrated water W3 and the permeated water W2 at a constant ratio without using electrical control.

  As shown in FIG. 6, the dilution device 18 includes a mixing tank 181, a positive displacement turbine portion 182 as a driving portion, a positive displacement pump portion 183 as a driven portion, a sixth check valve V66, and a seventh reverse valve. A stop valve V67. In addition, the dilution device 18 includes a first introduction line L201, a second introduction line L202, and a diluted concentrated water lead-out line L203.

  The mixing tank 181 is a tank in which the concentrated water W3 and the permeated water W2 separated by the RO membrane module 7 are mixed. In the mixing tank 181, concentrated water W3 that circulates through the first introduction line L201 due to water pressure from the RO membrane module 7, and permeated water W2 that circulates through the second introduction line L202 due to water pressure by the positive displacement pump unit 183 described below, Is introduced. The concentrated water W3 and the permeated water W2 mixed in the mixing tank 181 become diluted concentrated water W30. The diluted concentrated water W30 diluted by the dilution device 18 is supplied to the second silica concentration sensor SS2 via the diluted concentrated water deriving line L203. The upstream end of the diluted concentrated water outlet line L203 is connected to the mixing tank 181. The downstream end of the diluted concentrated water outlet line L203 is connected to the second silica concentration sensor SS2.

  The first introduction line L201 is a line for introducing the concentrated water W3 separated by the RO membrane module 7 flowing through the RO concentrated water return line L51 into the mixing tank 181 through the concentrated water introduction line L111. The concentrated water W3 is introduced into the first introduction line L201 by the water pressure of the RO membrane module 7. The water pressure of the concentrated water W3 flowing through the RO concentrated water return line L51 is higher than the water pressure of the permeated water W2 flowing through the permeated water line L21. The first introduction line L201 is connected to the RO concentrated water return line L51 via the concentrated water introduction line L111.

  The upstream end of the concentrated water introduction line L111 is connected to a connection portion J61 (see FIG. 2B). The connecting part J61 is disposed between the RO membrane module 7 and the connecting part J53 in the RO concentrated water return line L51. The downstream end of the concentrated water introduction line L111 is connected to the upstream end of the first introduction line L201.

In the first introduction line L201, a sixth check valve V66, a positive displacement turbine unit 182 and a mixing tank 181 are provided in order from the inlet side on the concentrated water introduction line L111 side.
The positive displacement turbine unit 182 is driven when being introduced into the mixing tank 181 by the water pressure of the concentrated water W3 separated by the RO membrane module 7 introduced into the first introduction line L201. The rotary shaft of the positive displacement turbine unit 182 rotates when a rotor (not shown) rotates due to the water pressure of the concentrated water W <b> 3 introduced into the positive displacement turbine unit 182. A rotary shaft of the positive displacement turbine unit 182 is connected to a rotary shaft of a positive displacement pump unit 183 described later by a connecting member 184.

  The second introduction line L202 is a line for introducing the permeated water W2 separated by the RO membrane module 7 flowing through the permeate water line L21 into the mixing tank 181 through the permeate water introduction line L112. The second introduction line L202 is connected to the permeated water line L21 via the permeated water introduction line L112.

  The upstream end portion of the permeated water introduction line L112 is connected to the connection portion J62 (see FIG. 2B). The connecting portion J62 is disposed between the RO membrane module 7 and the third check valve V63 in the permeate line L21. The downstream end of the permeated water introduction line L112 is connected to the upstream end of the second introduction line L202.

In the second introduction line L202, a seventh check valve V67, a positive displacement pump unit 183, and a mixing tank 181 are provided in order from the inlet side on the permeate introduction line L112 side.
The positive displacement pump unit 183 is driven by the drive of the positive displacement turbine unit 182. The positive displacement pump unit 183 generates a water pressure toward the mixing tank 181 and introduces the permeated water W2, which is a dilution water having a lower water pressure than the water pressure of the concentrated water W3, into the mixing tank 181. Specifically, the rotary shaft of the positive displacement pump unit 183 is rotated via the connecting member 184 as the rotary shaft of the positive displacement turbine unit 182 rotates. A rotary member (not shown) of the positive displacement pump unit 183 generates a water pressure for sending the permeate W2 toward the mixing tank 181 by rotating the rotary shaft of the positive displacement pump unit 183. Thereby, positive displacement pump part 183 introduces permeated water W2 lower than the water pressure of concentrated water W3 into mixing tank 181.

  In the present embodiment, the dilution device 18 configured as described above has a volume between the volume of the concentrated water W3 pumped by the positive displacement turbine unit 182 and the volume of the permeate water W2 pumped by the positive displacement pump unit 183. The ratio is 1: 2. That is, since the concentrated water W3 and the permeated water W2 are fed into the mixing tank 181 at a ratio of 1: 2, the dilution device 18 in the present embodiment has a mixing ratio of the concentrated water W3 and the permeated water W2 of 1: 2. It has become. The diluting device 18 in the present embodiment uses a hydraulic pressure of the concentrated water W3 from the RO membrane module 7 so that the mixing ratio of the concentrated water W3 and the permeated water W2 is 1: 2 with a mechanical configuration. It is configured. The mixing ratio of the concentrated water W3 and the permeated water W2 can be appropriately set by changing the volume ratio between the positive displacement turbine unit 182 and the positive displacement pump unit 183. For example, a rotor or gear having a geometric shape is used as the rotor of the positive displacement turbine unit 182 and the rotary member of the positive displacement pump unit 183.

  The diluted concentrated water W30 produced by mixing in the mixing tank 181 is introduced into the second silica concentration sensor SS2 through the diluted concentrated water introduction line L205. Here, the diluted concentrated water introduction line L205 shown in FIG. 6 corresponds to the inspection water introduction line L101 in the structure of the aforementioned silica concentration sensor shown in FIG. As shown in FIG. 6, the upstream end of the diluted concentrated water introduction line L205 is connected to the downstream end of the diluted concentrated water lead-out line L203 of the dilution device 18. The downstream end of the diluted concentrated water introduction line L205 is connected to the measurement cell 120 (see FIG. 4) inside the second silica concentration sensor SS2. In the middle of the diluted concentrated water introduction line L205 (test water introduction line L101), the electromagnetic valve 123 shown in FIG. 4 is also provided.

  The input operation unit 40 is an input interface that receives an input operation of a user or an administrator for selection related to the operation state of the device (for example, selection of operation / stop, release of alarm, etc.) and various settings related to the operation condition of the device. is there. The input operation unit 40 includes an operation panel that combines a display and button switches, a touch panel that directly operates on the display, and the like. The input operation unit 40 is electrically connected to the control unit 30. Information input from the input operation unit 40 is transmitted to the control unit 30.

  The main display unit 60 displays desired information. The main display unit 60 is electrically connected to the control unit 30. The main display unit 60 also functions as a notification unit that notifies a predetermined alarm by display. In the present embodiment, the main display unit 60 is configured to notify the alarm by display as the notification unit, but is not limited thereto. The notification by the notification means may be one or more of display, sound, light emission, and the like, for example. That is, the notification means may be configured by one or more of a display (liquid crystal display or the like), a buzzer, a speaker, a lamp, and the like.

  Next, the control unit 30 will be described. The control unit 30 is configured by a microprocessor (not shown) including a CPU and a memory. In the control unit 30, the CPU of the microprocessor executes various controls described later according to a predetermined program read from the memory. In the control unit 30, data and various programs for controlling the pure water production apparatus 1 are stored in the memory of the microprocessor. The microprocessor of the control unit 30 incorporates an integrated timer unit (hereinafter also referred to as “ITU”) that manages timekeeping and the like.

  As the flow rate feedback water amount control, the control unit 30 calculates the drive frequency of the pressurizing pump 5 by the speed type digital PID algorithm so that the detected flow rate value of the first flow rate sensor FM1 becomes a preset target flow rate value. Then, a current value signal (frequency designation signal) corresponding to the calculated value of the driving frequency is output to the inverter 6. The flow rate feedback water amount control by the control unit 30 will be described later.

  The controller 30 calculates the silica concentration of the concentrated water W3 separated by the RO membrane module 7 as the calculated silica concentration value Cc from the first detected silica concentration value Cp and the second detected silica concentration value Cm, and calculates the calculated silica concentration. The recovery rate (ratio of the flow rate of the first permeate to the flow rate of the supply water supplied to the RO membrane module 7) is adjusted so that the value Cc becomes the allowable silica concentration value Ca. This recovery rate control is executed in parallel with the above-described flow rate feedback water amount control.

  The control unit 30 calculates the allowable silica concentration value Ca by multiplying the silica solubility Ss of the concentrated water W3 determined from the detected temperature value T of the supply water W1 detected by the first temperature sensor TE1 by the safety factor.

The control unit 30 calculates the calculated silica concentration value Cc of the concentrated water W3 from the following formula (1).
Cc = [Cm · (Vc + Vp) −Cp · Vp] / Vc (1)
Vc [mL] is the sample water amount value of the concentrated water W3, Vp [mL] is the sample water amount value of the permeated water W2 (diluted water), and Cc [mgSiO ₂ / L] is the calculated silica concentration value of the concentrated water W3. Cp [mgSiO ₂ / L] was the first detected silica concentration value of the permeated water W2 (diluted water), and Cm [mgSiO ₂ / L] was the second detected silica concentration value of the first diluted concentrated water W30.

  The control unit 30 can employ, for example, the following first recovery rate control method and / or second recovery rate control method as a method of adjusting the recovery rate.

  As the first recovery rate control method, the control unit 30 maintains the flow rate of the permeate W2 separated by the RO membrane module 7 so that the calculated silica concentration value Cc becomes the allowable silica concentration value Ca, while maintaining the RO flow rate constant. The recovery rate is adjusted by increasing or decreasing the flow rate of the concentrated water W3 separated by the membrane module 7. Specifically, when the calculated silica concentration value Cc> the allowable silica concentration value Ca, the rotational speed of the pressure pump 5 is controlled so as to keep the target flow rate of the permeated water W2 constant, and the concentrated water W3. The first drain valve V32 to the third drain valve V34 are controlled so as to increase the flow rate, and the recovery rate is decreased. On the other hand, when the calculated silica concentration value Cc <allowable silica concentration value Ca, the rotational speed of the pressurizing pump 5 is controlled so that the target flow rate of the permeated water W2 is kept constant, and the flow rate of the concentrated water W3 is controlled. The first drain valve V32 to the third drain valve V34 are controlled so as to decrease, and the recovery rate is increased.

  As the second recovery rate control method, the control unit 30 maintains the flow rate of the concentrated water W3 separated by the RO membrane module 7 so that the calculated silica concentration value Cc becomes the allowable silica concentration value Ca, and RO The recovery rate is adjusted by increasing or decreasing the flow rate of the permeated water W2 separated by the membrane module 7. Specifically, when the calculated silica concentration value Cc> the allowable silica concentration value Ca, the first drain valve V32 to the third drain valve V34 are controlled so as to maintain the drain flow rate of the concentrated water W3 constant. Then, the rotational speed of the pressurizing pump 5 is controlled so as to reduce the target flow rate of the permeate W2, and the recovery rate is reduced. On the other hand, when the calculated silica concentration value Cc <the allowable silica concentration value Ca, the first drain valve V32 to the third drain valve V34 are controlled so as to keep the drain flow rate of the concentrated water W3 constant, and the permeated water. The rotational speed of the pressure pump 5 is controlled so as to increase the target flow rate of W2, and the recovery rate is increased.

  Next, flow rate feedback water amount control by the control unit 30 will be described. FIG. 7 is a flowchart illustrating a processing procedure when the control unit 30 executes the flow rate feedback water amount control. The process of the flowchart shown in FIG. 7 is repeatedly executed during operation of the pure water production apparatus 1.

In step ST101 shown in FIG. 7, the control unit 30 acquires the target flow rate value Q _p ′ of the permeated water W2. This target flow rate value Q _p ′ is, for example, a set value that is input to the memory of the control unit 30 by the device administrator via the input operation unit 40.

  In step ST102, the control unit 30 determines whether or not the time t measured by the ITU has reached 100 ms, which is the control period (Δt). In step ST102, when the control unit 30 determines that the time t measured by the ITU has reached 100 ms (YES), the process proceeds to step ST103. In step ST102, when the control unit 30 determines that the time measured by the ITU has not reached 100 ms (NO), the process returns to step ST102.

Step ST 103: In (step ST 102 YES judgment), the control unit 30 acquires the detected flow rate value _{Q p} of the first flow rate sensor FM1 as a feedback value.

In step ST 104, the control unit 30 detects the flow rate value obtained in step ST 103 (feedback value) _{Q p} and, as difference between the target flow rate value _{Q p} 'obtained in step ST101 becomes zero, velocity type digital PID The operation amount _Un is calculated by an algorithm. In the speed type digital PID algorithm, the operation amount change ΔU _n is calculated every control cycle Δt (100 ms), and this is added to the operation amount U _n−1 at the previous control cycle, thereby obtaining the current operation amount U. _n is determined.

An arithmetic expression used for the velocity type digital PID algorithm is expressed by the following expressions (2a) and (2b).
_{ΔU n = K p {(e} n -e n-1) + (Δt / T i) × e n + (T d / Δt) × (e n -2e n-1 + e n-2)} (2a)
U _n = U _n-1 + ΔU _n (2b)

In Expression (2a) and Expression (2b), Δt: control period, U _n : current operation amount, U _n-1 : operation amount at the previous control period, ΔU _n : change in operation amount from the previous time to this time. Minute, e _n : magnitude of current deviation, e _n-1 : magnitude of deviation at the previous control cycle, e _n-2 : magnitude of deviation at the previous control cycle, K _p : proportional gain, T _i : integration time, T _d : differentiation time. The size e _n of the current deviation is obtained by the following formula (3).
e _n = Q _p ′ −Q _p (3)

In step ST105, the control unit 30 uses the current operation amount U _n , the target flow rate value Q _p ′, and the maximum drive frequency of the pressurizing pump 5 (set value of 50 Hz or 60 Hz) according to a predetermined arithmetic expression, The drive frequency F [Hz] of the pressure pump 5 is calculated.

  In step ST <b> 106, the control unit 30 converts the calculated value of the drive frequency F into a corresponding current value signal (frequency designation signal: 4 to 20 mA), and outputs this current value signal to the inverter 6. Thereby, the process of this flowchart is complete | finished (it returns to step ST101). In step ST106, when the control unit 30 outputs a current value signal to the inverter 6, the inverter 6 supplies the driving power converted to the frequency specified by the input current value signal to the pressurizing pump 5. As a result, the pressurization pump 5 is driven at a rotational speed corresponding to the drive frequency input from the inverter 6.

Next, control for adjusting the recovery rate by the control unit 30 will be described.
In step ST201 shown in FIG. 8, the control unit 30 acquires the detected temperature value T of the supply water W1 from the first temperature sensor TE1.

  In step ST202, the control part 30 determines the silica solubility Ss with respect to water based on the acquired detected temperature value T. In addition, the control unit 30 calculates the allowable silica concentration value Ca by multiplying the silica solubility Ss by the safety factor.

  In step ST203, the first detected silica concentration value Cp of the permeated water W2 is acquired from the first silica concentration sensor SS1, and the second detected silica concentration value Cm of the diluted concentrated water W30 is acquired from the second silica concentration sensor SS2.

  In step ST204, the control unit 30 calculates the calculated silica concentration value Cc by the above equation (1) based on the first detection silica concentration value Cp and the second detection silica concentration value Cm.

In step ST205, the control unit 30 adjusts the recovery rate so that the calculated silica concentration value Cc becomes the allowable silica concentration value Ca. Specifically, for example, the control unit 30 executes the following first recovery rate control method or second recovery rate control method. For example, as the first recovery rate control method, the control unit 30 rotates the pressurizing pump 5 so as to maintain the target flow rate of the permeate W2 constant so that the calculated silica concentration value Cc becomes the allowable silica concentration value Ca. The recovery rate is adjusted by controlling the first drain valve V32 to the third drain valve V34 so as to control the speed and increase or decrease the flow rate of the concentrated water W3. Further, for example, as a second recovery rate control method, the control unit 30 uses the first drain valve so as to keep the drain flow rate of the concentrated water W3 constant so that the calculated silica concentration value Cc becomes the allowable silica concentration value Ca. The recovery rate is adjusted by controlling the rotation speed of the pressurizing pump 5 so as to control the V32 to the third drain valve V34 and reduce the target flow rate of the permeate W2.
Thereby, the process of this flowchart is complete | finished (it returns to step ST201). In the pure water manufacturing apparatus 1 according to the first embodiment, the recovery rate can be adjusted based on the silica concentration value of the concentrated water detected with high accuracy, and the precipitation of the silica-based scale can be suppressed.

  Next, an operation for notifying an alarm when the concentration of concentrated water locally increases inside the RO membrane module 7 will be described. FIG. 9 is a flowchart showing control in which an alarm is notified when the concentration of concentrated water is high inside the RO membrane module 7 in the control unit 30. The process of the flowchart shown in FIG. 9 is repeatedly executed during operation of the pure water production apparatus 1.

  In step ST301, the control unit 30 acquires the third A detection silica concentration value Cq from the third A silica concentration sensor SS3A. The control unit 30 acquires the third B detection silica concentration value Cr from the third B silica concentration sensor SS3B.

  In step ST302, the control unit 30 determines whether or not the acquired 3A detection silica concentration value Cq or 3B detection silica concentration value Cr is below a predetermined threshold value. When it is determined that the acquired 3A detection silica concentration value Cq exceeds the predetermined threshold (NO), there is a possibility that local silica overconcentration has occurred in the first submodule 71. Similarly, when it is determined that the acquired third B detection silica concentration value Cr exceeds a predetermined threshold (NO), there is a possibility that local overconcentration of silica has occurred in the second submodule 72. Therefore, when the determination in step ST302 is NO, the process proceeds to step ST303, and an alarm relating to silica overconcentration is notified. When the alarm is notified, the process of this flowchart ends (returns to step ST301). On the other hand, when it is determined that the acquired 3A detection silica concentration value Cq or 3B detection silica concentration value Cr is lower than the predetermined threshold (YES), the processing of this flowchart is ended as it is (return to step ST301). .

  According to the pure water manufacturing apparatus 1 which concerns on 1st Embodiment mentioned above, the following effects are show | played, for example.

  In the pure water production apparatus 1 according to the first embodiment, the RO membrane module 7 that separates the supply water W1 into the permeate water W2 and the concentrated water W3, and the concentrated water W3 separated by the RO membrane module 7 is purified into pure water. The silica concentration of the diluting device 18 for producing the diluted concentrated water W30 by mixing the permeated water (diluted water) W2 flowing through the apparatus 1 and the permeated water (diluted water) W2 flowing through the pure water producing device 1 is set to The first silica concentration sensor SS1 that detects the first detection silica concentration value Cp, and the second silica concentration sensor SS2 that detects the silica concentration of the first diluted concentrated water W30 produced by the dilution device 18 as the second detection silica concentration value Cm. Then, the silica concentration of the first concentrated water W3 is calculated as the calculated silica concentration value Cc from the first detected silica concentration value Cp and the second detected silica concentration value Cm, and the calculated silica concentration value Cc is the allowable silica concentration. As the value Ca, and a control unit 30 for adjusting the recovery rate (flow rate ratio of the RO membrane module 7 first permeate water W2 to the flow rate of feed water W1 is supplied to) the.

  Therefore, the concentration of silica in the concentrated water W3 can be calculated by using the permeated water W2 flowing through the pure water production apparatus 1 as dilution water and diluting the concentrated water W3 to produce the diluted concentrated water W30. it can. Accordingly, the silica concentration of the concentrated water W3 can be accurately detected using the second silica concentration sensor SS2 having a limited concentration measurement range, and the concentration is recovered based on the silica concentration of the concentrated water W3 detected with high accuracy. The rate can be adjusted. Therefore, precipitation of silica-based scale can be effectively suppressed.

  In the present embodiment, the diluting device 18 includes a mixing tank 181 in which the concentrated water W3 separated by the RO membrane module 7 and the permeated water W2 are mixed, and the concentrated water W3 separated by the RO membrane module 7. A positive displacement turbine section 182 that is driven when introduced into the mixing tank 181 by water pressure, and a positive displacement pump section 183 that is driven by the drive of the positive displacement turbine section 182, and the water pressure toward the mixing tank 181. And a positive displacement pump unit 183 that introduces diluted water having a lower water pressure than the water pressure of the concentrated water W3 into the mixing tank. Therefore, by using the mechanical dilution device 18 that is driven by the pressure of the concentrated water W3 from the RO membrane module 7, the permeated water W2 can be simply configured with respect to the concentrated water W3 without using electrical control. Can be mixed and diluted.

  In this embodiment, the RO membrane module 7 includes three submodules 71, 72, and 73. The three submodules 71, 72, and 73 are separated from the three submodules 71, 72, and 73, respectively. The 3A silica concentration sensor SS3A for detecting the 3A detection silica concentration value or the 3B silica concentration sensor SS3B for detecting the 3B detection silica concentration value are connected in series so that the concentrated water is supplied to the next submodule. And a main display unit 60 that notifies an alarm, and the control unit 30 causes the main display unit 60 to display when the 3A detection silica concentration value or the 3B detection silica concentration value exceeds a predetermined threshold value. Announcement is executed. Therefore, by measuring the silica concentration of the concentrated water between the submodules 71, 72, and 73 inside the RO membrane module 7, a local silica concentration abnormality (overconcentration) occurs inside the RO membrane module 7. By monitoring whether there is an abnormality in the silica concentration of the concentrated water, it is possible to make the user recognize that the risk of silica-based scale adhesion has increased. Thereby, it is possible to prompt the user to review the flushing frequency or circulation ratio (ratio of the flow rate of the concentrated water to the flow rate of the permeated water) for the RO membrane module 7.

(Second Embodiment)
Next, a pure water producing apparatus 1A according to a second embodiment of the present invention will be described with reference to FIGS. 10 and 11A to 11C. FIG. 10 is an overall schematic diagram of a pure water producing apparatus 1A according to the second embodiment. FIG. 11A is a front part of the entire configuration diagram of the pure water producing apparatus 1A according to the second embodiment. FIG. 11B is the middle part of the overall configuration diagram of the pure water producing apparatus 1A according to the second embodiment. FIG. 11C is a rear part of the entire configuration diagram of the pure water producing apparatus 1A according to the second embodiment.

  In the second embodiment, differences from the first embodiment will be mainly described. For this reason, the same code | symbol is attached | subjected about the same (or equivalent) structure as 1st Embodiment, and detailed description is abbreviate | omitted. The description of the first embodiment is appropriately applied to points that are not particularly described in the second embodiment.

  The deionized water production apparatus 1A according to the second embodiment is different from the deionized water production apparatus 1 according to the first embodiment in that the decarbonation apparatus 15 is provided on the downstream side of the RO membrane module 7. The deionized water production apparatus according to the first embodiment is further provided with an electrodeionization stack (hereinafter also referred to as an “EDI stack”) 16 as a deionization section on the downstream side thereof, and the configuration around these. Mainly different from 1.

  Moreover, 1 A of pure water manufacturing apparatuses which concern on 2nd Embodiment connect the downstream edge part of the 2nd introduction line L202 in the dilution apparatus 18 of 1st Embodiment to the permeate line L21 via the permeate introduction line L112. However, the first embodiment is provided with the first silica concentration sensor SS1 in the permeated water line L21 in that it is connected to the desalted water line L3 via the desalted water introduction line L113. Instead, it differs from the pure water producing apparatus 1 according to the first embodiment in that the demineralized water line L3 includes the fourth silica concentration sensor SS4.

  As shown in FIG. 10, the pure water producing apparatus 1A according to the second embodiment includes a first optional device OP1, a prefilter 4, a second optional device OP2, a pressurizing pump 5, an inverter 6, and an RO. Membrane module 7, decarboxylation device 15, first flow path switching valve V71, EDI stack 16, second flow path switching valve V72, third optional device OP3, control unit 30A, and input operation unit 40 And a DC power supply device 50 and a main display unit 60.

  As shown in FIG. 11A, in the pure water producing apparatus 1A according to the second embodiment, the second optional device OP2 is connected to the connection portion J5 of the second supply water line L12, and the soft water supply line L24 is not connected. . In the pure water producing apparatus 1A according to the second embodiment, the concentrated water W7 discharged from the EDI stack 16 (concentration chamber 162) is supplied to the sealed water tank of the decarboxylation device 15 and used as the sealed water W8. .

  As shown in FIGS. 11B and 11C, the permeate line L21 of the present embodiment includes a front-stage permeate line L211, a middle-stage permeate line L212, a desalting chamber inflow line L213, and a concentration chamber inflow line L214. Have.

  In the present embodiment, as shown in FIG. 11C, the downstream end of the front-stage permeate line L211 is connected to the middle-stage permeate line L212 and the RO permeate return line L41 via the first flow path switching valve V71. It is connected to the.

  As shown in FIG. 11B, in the pure water manufacturing apparatus 1A according to the second embodiment, a connection portion J59 is provided between the supply water supply valve V31 and the connection portion J51 in the second supply water line L12. The downstream end of the desalted water return line L42 described later is connected to the connecting portion J59.

  As shown in FIG. 11C, the first flow path switching valve V71 of the present embodiment distributes the permeate W2 separated by the RO membrane module 7 toward the EDI stack 16 via the middle permeate line L212. It is possible to switch to a flow path (water sampling side flow path) or a flow path (circulation side flow path) that circulates toward the supply water line L1 on the upstream side of the RO membrane module 7 via the RO permeate return line L41. It is a valve.

  In this embodiment, the downstream end of the middle stage permeate line L212 is connected to the upstream end of the desalination chamber inflow line L213 and the upstream end of the concentrating chamber inflow line L214 at the branch J71. Has been.

  The upstream end of the middle permeate line L212 is connected to the first flow path switching valve V71. The downstream end of the middle permeate water line L212 is connected to the upstream end of the desalting chamber inflow line L213 and the upstream end of the concentrating chamber inflow line L214 at the branch J71.

  The downstream end of the desalting chamber inflow line L213 is connected to the primary port of the EDI stack 16 (inlet side of the desalting chamber 161). A connecting portion J33 is disposed in the desalting chamber inflow line L213. The downstream end of the concentrating chamber inflow line L214 is connected to a primary port (each inlet side of the concentrating chamber 162) of the EDI stack 16. The concentrating chamber inflow line L214 is provided with a fifth constant flow valve V55 and a connecting portion J34 in order from the upstream side.

The EDI stack 16 demineralizes (deionizes) the permeated water W2 (first permeated water) separated from the supply water W1 by the RO membrane module 7, and demineralized water W6 as deionized water and concentrated water W7. It is a water treatment equipment that obtains. The EDI stack 16 is electrically connected to the DC power supply device 50 (see FIG. 10 ). A DC voltage is applied to the EDI stack 16 from the DC power supply device 50. The EDI stack 16 is energized by the DC voltage applied from the DC power supply device 50 and operates.

  The DC power supply device 50 applies a DC voltage between the pair of electrodes of the EDI stack 16. The DC power supply device 50 is electrically connected to the control unit 30A. The DC power supply device 50 applies a DC voltage to the EDI stack 16 in response to the voltage specifying signal (or current specifying signal) input by the control unit 30A.

  In the EDI stack 16, a cation exchange membrane and an anion exchange membrane (not shown) are alternately arranged between a pair of electrodes. The inside of the EDI stack 16 is partitioned into a desalting chamber 161 and a concentration chamber 162 (including an anode chamber and a cathode chamber) by these ion exchange membranes. The desalting chamber 161 is filled with an ion exchanger (not shown). As an ion exchanger filled in the desalting chamber 161, for example, an ion exchange resin or an ion exchange fiber is used. FIG. 11C schematically shows a plurality of desalting chambers 161 and concentration chambers 162 partitioned inside the EDI stack 16.

  A desalting chamber inflow line L213 through which the permeated water W2 flows is connected to the inlet side of the desalting chamber 161. On the outlet side of the desalting chamber 161, a desalted water line L3 through which the desalted water W6 discharged from the ions in the desalting chamber 161 is discharged is connected. A concentrating chamber inflow line L214 through which the permeated water W2 flows is connected to the inlet side of the concentrating chamber 162. An EDI concentrated water line L52 for circulating the concentrated water W7 that has been concentrated and discharged is connected to the outlet side of the concentration chamber 162.

  The permeated water W2 flowing through the permeated water line L21 flows into each of the desalting chamber 161 and the concentration chamber 162. Residual ions contained in the permeated water W2 are captured by an ion exchanger (not shown) filled in the desalting chamber 161 to become desalted water W6. The desalted water W6 is sent to the demand location via the desalted water line L3 (described later). Further, residual ions captured by the ion exchanger in the desalting chamber 161 move to the concentration chamber 162 by the electric energy of the applied DC voltage. And the water containing a residual ion is sent out toward the decarbonation apparatus 15 through the EDI concentrated water line L52 (after-mentioned) as the concentrated water W7. The concentrated water W7 sent to the decarbonation device 15 is used as the sealed water W8, and is then discharged out of the device via the sealed water discharge line L71.

  The desalted water line L3 is a line for sending the desalted water W6 obtained by the EDI stack 16 to the demand point as pure water. The demineralized water line L3 includes an upstream demineralized water line L31 and a downstream demineralized water line L32.

  The upstream end of the upstream demineralized water line L31 is connected to the secondary port of the EDI stack 16 (the outlet side of the demineralized chamber 161). The downstream end of the upstream demineralized water line L31 is connected to the downstream demineralized water line L32 and the demineralized water return line L42 via the second flow path switching valve V72. In the upstream demineralized water line L31, a connecting portion J36, a connecting portion J37, a connecting portion J38, a seventh on-off valve V17, a connecting portion J65, a connecting portion J64, and a second flow path switching valve V72 are provided in this order from the upstream side. It has been. The seventh on-off valve V17 is a manual valve that can be operated to open and close the upstream demineralized water line L31.

  The second flow path switching valve V72 is a flow path (water sampling side flow path) for sending the desalted water W6 obtained in the desalination chamber 161 of the EDI stack 16 toward the demand point via the downstream side desalted water line L32. ) Or an automatic valve that can be switched to a flow path (circulation side flow path) that circulates toward the supply water line L1 upstream of the RO membrane module 7 via the desalted water return line L42. The second flow path switching valve V72 is configured by, for example, an electric or electromagnetic three-way valve. The second flow path switching valve V72 is electrically connected to the control unit 30A. The switching of the flow path in the second flow path switching valve V72 is controlled by a flow path switching signal transmitted from the control unit 30A.

  The second flow path switching valve V72 performs a process of sending the demineralized water W6 obtained in the EDI stack 16 from the demineralized water line L3 to the demand point by being switched to the water sampling side flow path by the control unit 30. It functions as an executable sending means.

  The upstream end of the downstream demineralized water line L32 is connected to the second flow path switching valve V72. The downstream end of the downstream demineralized water line L32 is connected to an apparatus or the like (not shown) at the demand point.

  The desalted water return line L42 is a line for returning the desalted water W6 obtained in the desalting chamber 161 of the EDI stack 16 to the upstream side of the RO membrane module 7 from the middle of the desalted water line L3. In the present embodiment, the upstream end of the desalted water return line L42 is connected to the second flow path switching valve V72. The downstream end of the desalted water return line L42 is connected to the connecting portion J59. The desalted water return line L42 is a line for returning the desalted water W6 obtained in the desalting chamber 161 of the EDI stack 16 to the upstream side (supply water line L1) of the RO membrane module 7. A fifth check valve V65 is provided on the upstream side of the desalted water return line L42.

  The EDI concentrated water line L52 is a line for sending the concentrated water W7 discharged from the concentration chamber 162 of the EDI stack 16 to the decarboxylation device 15. The upstream end of the EDI concentrated water line L52 is connected to the secondary port of the EDI stack 16 (the outlet side of the concentration chamber 162). The downstream end of the EDI concentrated water line L52 is connected to the decarboxylation device 15.

  The pure water manufacturing apparatus 1A according to the present embodiment includes a fifth pressure gauge P5 and a sixth pressure gauge P6 in addition to the first pressure gauge P1 to the fourth pressure gauge P4. As shown in FIG. 11C, the fifth pressure gauge P5 is connected to the EDI concentrated water line L52 at the connection portion J35. The sixth pressure gauge P6 is connected to the demineralized water line L3 at the connection portion J36.

  The pure water manufacturing apparatus 1A according to the present embodiment includes a third pressure sensor PS3 and a fourth pressure sensor PS4 in addition to the first pressure sensor PS1 and the second pressure sensor PS2. The third pressure sensor PS3 is connected to the desalting chamber inflow line L213 at the connection portion J33. The connection part J33 is arrange | positioned in the middle of the desalination chamber inflow line L213. The fourth pressure sensor PS4 is connected to the concentration chamber inflow line L214 at the connection portion J34. The connection portion J34 is disposed between the fifth constant flow valve V55 and the EDI stack 16 in the concentration chamber inflow line L214.

  The pure water manufacturing apparatus 1A according to the present embodiment includes a first specific resistance sensor RS1 in addition to the second specific resistance sensor RS2. 1st specific resistance sensor RS1 is connected to the desalted water line L3 in the connection part J37. The connection portion J37 is disposed between the EDI stack 16 and the second flow path switching valve V72 in the desalted water line L3. As with the second specific resistance sensor RS2, the first specific resistance sensor RS1 incorporates a temperature sensor for temperature compensation of the measured specific resistance value. Therefore, the second specific resistance sensor RS2 can measure the water temperature of the desalted water W6.

  The first specific resistance sensor RS1 is electrically connected to the control unit 30A similarly to the second specific resistance sensor RS2. The specific resistance (and temperature) of the desalted water W6 measured by the first specific resistance sensor RS1 is transmitted as a detection signal to the control unit 30A.

  The pure water manufacturing apparatus 1A according to the present embodiment includes a second flow rate sensor FM2 in addition to the first flow rate sensor FM1. The second flow rate sensor FM2 is connected to the demineralized water line L3 at the connection portion J38. The connection part J38 is arrange | positioned between the EDI stack 16 and the connection part J24 (after-mentioned) in the desalted water line L3.

  The pure water manufacturing apparatus 1A according to the second embodiment includes a fourth silica concentration sensor SS4 instead of the first silica concentration sensor SS1 in the first embodiment. The fourth silica concentration sensor SS4 is a device that detects the silica concentration of the desalted water W6 flowing through the desalted water line L3 as the first detected silica concentration value Cp. The fourth silica concentration sensor SS4 is connected to the demineralized water line L3 at the connection portion J65. The connection portion J65 is disposed between the EDI stack 16 and the second flow path switching valve V72 in the desalted water line L3.

  In the second embodiment, the diluting device 18 is attached to the second silica concentration sensor SS2 as in the first embodiment. The diluting device 18 of the second embodiment differs from the diluting device 18 of the first embodiment in that the permeated water W2 is used as the diluting water in the first embodiment, whereas the desalted water W6 is used as the diluting water. The diluting device 18 mixes the concentrated water W3 separated by the RO membrane module 7 with the desalted water W6 (diluted water) flowing through the pure water producing apparatus 1A, thereby diluting the concentrated water W30 (second diluted concentrated water). Manufacturing. Thereby, the dilution apparatus 18 dilutes the concentrated water W3 separated by the RO membrane module 7 using the demineralized water W6 obtained by the EDI stack 16 as the dilution water.

  In the diluting device 18 of the second embodiment, the second introduction line L202 replaces the desalted water W6 obtained by the EDI stack 16 flowing through the desalted water line L3 with the permeated water introduction line L112 of the first embodiment. This is a line that is introduced into the mixing tank 181 via the desalted water introduction line L113 (see FIG. 6). The upstream end of the desalted water introduction line L113 is connected to a connection portion J64 (see FIG. 11C). The downstream end of the desalted water introduction line L113 is connected to the upstream end of the second introduction line L202 (see FIG. 6). The desalted water introduction line L113 is connected to the desalted water line L3 (upstream desalted water line L31) at the connection portion J64 (see FIG. 11C). The connection portion J64 is disposed between the EDI stack 16 and the second flow path switching valve V72 in the upstream demineralized water line L31.

  The control unit 30A performs control similar to the flow rate feedback constant flow rate control described in the first embodiment. Moreover, the control part A performs control which adjusts the collection | recovery rate of the permeated water W2 so that the calculation silica density | concentration value Cc in 1st Embodiment becomes the allowable silica density | concentration value Ca. The second silica concentration sensor SS2 in the second embodiment is different from the first embodiment in that the permeated water W2 is used as the dilution water instead of the permeated water W2 as the dilution water. Therefore, in the second embodiment, the control unit 30A calculates the calculated silica concentration value Cc when the dilution water is the desalted water W6. Specifically, in the above formula (1) in the first embodiment, in the second embodiment, Vp in the above formula (1) is the sample water amount value of the demineralized water W6, and Cp is the first value of the demineralized water W6. One detection silica concentration value. Then, the control unit 30A calculates the calculated silica concentration value Cc from the above equation (1) using Vp and Cp related to the desalted water W6, and the calculated silica concentration value Cc is the allowable silica as in the first embodiment. The recovery rate is adjusted so that the concentration value Ca is obtained.

  Also in the pure water manufacturing apparatus 1A of the second embodiment described above, the same effect as the pure water manufacturing apparatus 1 of the first embodiment can be obtained. That is, the silica concentration of the concentrated water W3 can be calculated by using the desalted water W6 flowing through the pure water manufacturing apparatus 1A as dilution water and diluting the concentrated water W3 to produce the diluted concentrated water W30. it can. Accordingly, the silica concentration of the concentrated water W3 can be accurately detected using the second silica concentration sensor SS2 having a limited concentration measurement range, and the concentration is recovered based on the silica concentration of the concentrated water W3 detected with high accuracy. The rate can be adjusted. Therefore, precipitation of silica-based scale can be effectively suppressed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can be implemented in various forms.

  In the said embodiment, the example which calculates the drive frequency of the pressurization pump 5 by the speed type PID algorithm was demonstrated. Not limited to this, the driving frequency of these pressurizing pumps may be calculated by a position type PID algorithm. Further, the drive frequency may be calculated not only by the PID algorithm but also by the P algorithm or the PI algorithm.

  In the above embodiment, the example in which the current value signal is output as the frequency designation signal from the control units 30 and 30A to the inverter 6 has been described. However, the present invention is not limited to this, and a voltage value signal (for example, 0 to 10 V) may be output from the control units 30 and 30 </ b> A as a frequency designation signal to the inverter 6.

  In the said embodiment, the example which used the soft water W12 which removed the hardness component contained in the raw | natural water W11 as the supply water W1 was demonstrated. Not limited to this, the raw water W11 may be water pre-treated with a ferric-manganese removal device, a sand filtration device, a microfiltration membrane device, an ultrafiltration membrane device, or the like as the supply water W1. In addition, as raw | natural water W11, groundwater, a tap water, etc. can be used, for example.

  Moreover, in the said 1st Embodiment, in the pure water manufacturing apparatus 1 provided with the 1 stage | paragraph RO membrane module 7, the case where the permeated water W2 isolate | separated by the RO membrane module 7 was used as dilution water was demonstrated. However, the present invention is not limited to this, and in a pure water production apparatus including a two-stage RO membrane module arranged in series, a downstream permeated water separated by a downstream RO membrane module may be used as the dilution water. Specifically, a first-stage RO membrane module (first reverse osmosis membrane module) that separates supply water into first-stage permeated water (first permeated water) and first-stage concentrated water (first concentrated water); A pure water production apparatus comprising: a post-stage RO membrane module (second reverse osmosis membrane module) that separates the separated pre-stage permeate into second-stage permeate (second permeate) and post-stage concentrate (second concentrate) In this case, as the permeated water, the rear permeate separated by the rear RO membrane module may be used.

  Moreover, in the said 2nd Embodiment, in the pure water manufacturing apparatus provided with the 1 stage RO membrane module 7 and the EDI stack 16 provided in the back | latter stage of the 1 stage RO membrane module, EDI stack is used as dilution water. The case where the desalted water W6 obtained by No. 16 was used was demonstrated. However, the present invention is not limited to this. In a pure water production apparatus including a two-stage RO membrane module arranged in series and an EDI stack provided at the rear stage of the two-stage RO membrane module, the EDI stack is used as dilution water. You may use the desalted water manufactured by this, or the latter stage permeated water isolate | separated by the latter stage RO membrane module.

  In the second embodiment, the demineralized water W6 obtained by deionizing the permeated water W2 separated by the RO membrane module 7 using the EDI stack 16 has good water quality and extremely low silica concentration. it is conceivable that. Therefore, without providing a sensor for detecting the silica concentration of the demineralized water W6 as the dilution water, the silica concentration of the demineralized water W6 as the dilution water obtained by the EDI stack 16 is regarded as zero, and the above formula ( In 1), the first detected silica concentration value Cp is set to zero, and the calculated silica concentration value Cc can be calculated from the second detected silica concentration value Cm. Thereby, the calculation silica concentration value Cc of the concentrated water W3 can be calculated with a simple configuration without providing a sensor for detecting the silica concentration of the demineralized water W6 as dilution water.

  Further, in the first embodiment, the first silica concentration sensor SS1 and the second silica concentration sensor SS2 are configured as separate silica concentration sensors, and in the second embodiment, the fourth silica concentration sensor SS4 and the second silica concentration sensor. By configuring SS2 as a separate silica concentration sensor, the calculated silica concentration value is calculated from each detected silica concentration value, but is not limited thereto. The first silica concentration sensor SS1 and the second silica concentration sensor SS2 (or the fourth silica concentration sensor SS4 and the second silica concentration sensor SS2) are single silica capable of switching between two or more different concentration measurement ranges. You may comprise by a concentration sensor (single silica concentration detection means).

  For example, a single fifth silica concentration sensor SS5 can be configured with the configuration shown in FIG. FIG. 12 is a diagram when the first silica concentration sensor SS1 and the second silica concentration sensor SS2 in the first embodiment are configured by a single fifth silica concentration sensor SS5. The configuration of the fifth silica concentration sensor SS5 is shown in FIG. As shown in FIG. 12, the pure water production apparatus includes a dilution water bypass line L206 and a dilution water circulation valve 124 in addition to the configuration shown in FIG. The dilution water bypass line L206 is a line for directly introducing the permeated water W2 (desalted water W6) flowing through the permeated water introduction line L112 into the fifth silica concentration sensor SS5. The dilution water bypass line L206 connects the permeated water introduction line L112 and the dilution concentrated water introduction line L205. The upstream end of the dilution water bypass line L206 is connected to a connection portion J67 provided in the middle of the permeate introduction line L112. The upstream end of the dilution water bypass line L206 is connected to a connection portion J66 provided in the middle of the dilution concentrated water introduction line L205. The dilution water flow valve 124 is provided in the middle of the dilution water bypass line L206.

  In such a configuration, the introduction of the diluted concentrated water W30 or the diluted water (permeated water W2, desalted water W6) into the concentration sensor is selectively performed by switching between opening and closing of the electromagnetic valve 123 and the diluted water circulation valve 124. It can be carried out. As a result, the calculated silica concentration value Cc of the concentrated water W3 can be calculated while using the single fifth silica concentration sensor SS5. In this embodiment, two different concentration measurement ranges can be switched. However, the present invention is not limited to this, and an introduction line and a switching valve are provided as appropriate so that two or more different concentration measurement ranges can be switched. Also good.

  Moreover, in the said embodiment, the detected temperature value T of the supply water W1 detected by 1st temperature sensor TE1 was demonstrated to the example as water temperature by which the silica solubility Ss of the concentrated water W3 is determined. However, the detection target of the water temperature is not limited to the supply water W1. The temperature of the supply water W1 supplied from the primary side inlet port of the RO membrane module 7 and the temperature of the concentrated water W3 discharged from the primary side outlet port are water flowing through the same primary side in the RO membrane module 7. The temperature can be considered constant. Therefore, the detected temperature value T of the concentrated water W3 separated by the RO membrane module 7 may be used as the water temperature at which the silica solubility Ss of the concentrated water W3 is determined.

  Moreover, in the said embodiment, the example which adjusts the waste_water | drain flow volume of the concentrated water W3 in steps was selected by selecting the open number of the 1st drain valve V32-the 3rd drain valve V34. For example, the RO concentrated water discharge line L61 may be provided with a proportional control valve without branching the RO concentrated water discharge line L61. In this case, the flow rate of the concentrated water W3 can be adjusted by transmitting a current value signal from the control unit (30, 30A) to the proportional control valve to control the valve opening.

  Moreover, in the said embodiment, although the number of the submodules of the RO membrane module 7 was set to three, it is not limited to this, The number of submodules may be two and may be four or more. Good.

1,1A pure water production equipment (water treatment equipment)
7 RO membrane module (first reverse osmosis membrane module)
16 EDI stack (Electrodeionization stack: Deionization part)
18 Dilution device (dilution means)
30 Control part 60 Main display part (notification means)
71 First submodule (submodule)
72 Second submodule (submodule)
73 Third submodule (submodule)
181 Mixing tank 182 Positive displacement turbine unit (drive unit)
183 Positive displacement pump unit (driven unit)
SS1 first silica concentration sensor (first silica concentration detecting means)
SS2 Second silica concentration sensor (second silica concentration detection means, fourth silica concentration detection means)
SS3A 3A silica concentration sensor (third silica concentration detecting means)
SS3B 3B silica concentration sensor (third silica concentration detecting means)
SS4 Fourth silica concentration sensor (first silica concentration detecting means)
SS5 5th silica concentration sensor (single silica concentration measuring means)
TE1 first temperature sensor (temperature detection means)
W1 supply water W2 permeate (first permeate)
W3 concentrated water (first concentrated water)
W6 Demineralized water (deionized water)
W7 concentrated water W30 diluted concentrated water (first diluted concentrated water, second diluted concentrated water)

Claims (12)

A water treatment device,
A first reverse osmosis membrane module that separates supply water into first permeate and first concentrated water;
Dilution means for producing the first diluted concentrated water by mixing the first concentrated water separated by the first reverse osmosis membrane module with the diluted water flowing through the water treatment device,
First silica concentration detection means for detecting the silica concentration of the dilution water flowing through the water treatment device as a first detection silica concentration value;
Second silica concentration detection means for detecting the silica concentration of the first diluted concentrated water produced by the dilution means as a second detection silica concentration value;
From the first detected silica concentration value and the second detected silica concentration value, the silica concentration of the first concentrated water separated by the first reverse osmosis membrane module is calculated as the calculated silica concentration value, and the calculated silica concentration value A control unit that adjusts the recovery rate, which is the ratio of the flow rate of the first permeated water to the flow rate of the supplied water supplied to the first reverse osmosis membrane module, so that becomes an allowable silica concentration value;
A water treatment apparatus comprising: The water treatment device according to claim 1, wherein the dilution water flowing through the water treatment device is first permeated water separated by the first reverse osmosis membrane module. A second reverse osmosis membrane module for separating the first permeate separated by the first reverse osmosis membrane module into a second permeate and a second concentrated water;
The water treatment device according to claim 1, wherein the dilution water flowing through the water treatment device is second permeated water separated by the second reverse osmosis membrane module. A deionization unit for deionizing the first permeated water separated by the first reverse osmosis membrane module to obtain deionized water and concentrated water;
The water treatment device according to claim 1, wherein the dilution water flowing through the water treatment device is deionized water obtained by the deionization unit. Temperature detecting means for detecting the temperature of the feed water or the temperature of the first concentrated water separated by the first reverse osmosis membrane module as a detected temperature value;
The water treatment device according to any one of claims 1 to 4, wherein the control unit calculates the allowable silica concentration value by multiplying the silica solubility of the first concentrated water determined from the detected temperature value by a safety factor. Vc is the sample water amount value of the first concentrated water, Vp is the sample water amount value of the diluted water, Cc is the calculated silica concentration value of the first concentrated water, Cp is the first detected silica concentration value of the diluted water, and Cm is When the second detection silica concentration value of the first diluted concentrated water is used, the control unit calculates the calculated silica of the first concentrated water from the calculation formula of Cc = [Cm · (Vc + Vp) −Cp · Vp] / Vc. The water treatment apparatus according to claim 1, wherein the concentration value Cc is calculated. The control unit maintains a constant flow rate of the first permeated water separated by the first reverse osmosis membrane module and increases or decreases a flow rate of the first concentrated water separated by the first reverse osmosis membrane module. The water treatment apparatus according to any one of claims 1 to 6, wherein the recovery rate is adjusted so that the calculated silica concentration value becomes the allowable silica concentration value. The controller maintains a constant flow rate of the first concentrated water separated by the first reverse osmosis membrane module and increases or decreases a flow rate of the first permeated water separated by the first reverse osmosis membrane module. The water treatment apparatus according to any one of claims 1 to 6, wherein the recovery rate is adjusted so that the calculated silica concentration value becomes the allowable silica concentration value. The dilution means includes a mixing tank in which the first concentrated water and the diluted water separated by the first reverse osmosis membrane module are mixed, and the water pressure of the first concentrated water separated by the first reverse osmosis membrane module. A driving unit that is driven when being introduced into the mixing tank; and a driven unit that is driven by the driving of the driving unit, and generates water pressure toward the mixing tank to generate the first concentrated water. The water treatment apparatus according to any one of claims 1 to 8, further comprising: a driven portion that introduces dilution water having a lower water pressure than the water pressure into the mixing tank. The said 1st silica density | concentration detection means and the said 2nd silica density | concentration detection means are comprised by the single silica density | concentration measurement means which can switch a 2 or more different density | concentration measurement range, either. Water treatment equipment. The first reverse osmosis membrane module comprises a plurality of submodules,
The plurality of submodules are connected in series so that the concentrated water separated from each of the plurality of submodules is supplied to the next submodule,
The water treatment device includes a third silica concentration detection means for detecting a silica concentration of concentrated water discharged from a sub-module other than the most downstream of the plurality of sub-modules as a third detection silica concentration value, and an alarm. An informing means for informing,
The water treatment apparatus according to any one of claims 1 to 10, wherein the control unit performs notification by the notification unit when the third detected silica concentration value exceeds a predetermined threshold value. A water treatment device,
A first reverse osmosis membrane module that separates supply water into first permeate and first concentrated water;
A deionization unit that obtains deionized water and concentrated water by deionizing the first permeated water separated by the first reverse osmosis membrane module;
Dilution means for producing second diluted concentrated water by mixing deionized water as dilution water flowing through the water treatment device with the first concentrated water separated by the first reverse osmosis membrane module,
Fourth silica concentration detection means for detecting the silica concentration of the second diluted concentrated water produced by the dilution means as a fourth detection silica concentration value;
The first concentrated water separated by the first reverse osmosis membrane module from the fourth detected silica concentration value, assuming that the silica concentration of deionized water as dilution water obtained by the deionization unit is zero. Of the first permeated water with respect to the flow rate of the supplied water supplied to the first reverse osmosis membrane module so that the calculated silica concentration value becomes an allowable silica concentration value. A control unit that adjusts the recovery rate as a ratio;
A water treatment apparatus comprising:

Images